I actually started this right after I watched said episode and cranked it out as fast as possible. The writers sure dragged out that subplot for a long time, but I’m glad they finally decided to tie up that loose end.
 
Their task is to help other ponies get their cutie marks? Sounds like cutie mark-ception to me, ha ha.
 
Drawn in Inkscape… as if you didn’t already know that. :P
 
Not sure if this qualifies as wallpaper-grade art, but if this happens to suit your fancy, I won’t stop you. Enjoy everypony!
 
SVG available here: https://www.dropbox.com/s/x110216vv67h7p2/CMC%20Cutie%20Marks.svg?dl=0